Lighting up LEDs (more complicated than may seem)

Hi all,

Basically my problem is I have to light up 40 LEDs, dependant on data from a text file, however, there is a sequence of 8 to be lighted up in turn out of the 40. between each LED being lighted, I would like to send data back, by two contacts "detecting" each other, then the Next Led will light up.. and so on. I have knowledge of C# and have not purchased an Arduino board. How would i first approach this problem? i would like to create a prototype first, say about 5 LEDs, as a proof of concept to my team.

Thanks, Josh.

How would i first approach this problem?

First write a clear specification of what you want to do.

Everything you have mentioned sounds like it should be possible, but what exactly you are trying to do is far from clear.

there is a sequence of 8 to be lighted up in turn out of the 40.

This is very vague.

by two contacts "detecting" each other

I have no idea what you are trying to say. As a guess do you mean somebody has to push a button?

Right okay,

After processing the text file(specifying 8 LEDs to be lit up in sequence), the first LED will light up, and wait until a button has been pressed (essentially), then the first LED will go out, and the next in the sequence will light up.. then when button is pressed.. next one... etc.

Sorry for the bad explanation, thinking it too complicated than needed, any questions happy to help, Thanks, Josh.

That explanation is much clearer. The arduino once it knows which 8 LEDs out of the 40 you want to light up can respond to button presses and make the LEDs come on.

The things you need answers to are how to power the LEDs and how to multiplex the output from the arduino to drive the LEDs (the arduino does not have 40 pins). This can be done, and its not too difficult, but I am a newbie too.

The things you have still not explained are why you need a "text file" to specify the 8 LEDs to light and how the information in the file is supposed to get onto the arduino. Also how big the file is.

I am guessing that what you want to do is illuminate 8 LEDs, then move to a different 8 and so in a sequence? If the sequence is fixed then you could store it on the arduino, how you store it depends on how long the sequence is, if its not long then maybe you could just store it in memory.

If the sequence is not fixed then how do you plan to get the information into the arduino? For example it could send it over a serial link.

A fuller explanation of what you are trying to do will get more responses and better answers.

Serial in parallel out shift register. Use arduino to set the input of the shift register and then you clock it with another arduino pin. The pulses would have to start from LED1 every time. Unless you wired each input of the serial register to a different pin on the duino, but alas you would be limited to every 8 leds is the one the pulse train can start from. The parallel output drive each individual LED. And every clock pulse would be the "switch" mentioned earier, triggered by some thing understand at least a little? i hope so, if not search shift registers or LED multiplexing in that awesome little box top left that has a littler button that says search. you will find what you need. Good luck. -Erik